Dispensing valves for high viscosity fluids (up to 600,000 centipoise) such as sealants and adhesives are of course well known. Such valves typically have an air operated cylinder which controls a fluid valve. Such valves have often been awkward to use because of the need to plumb both fluid and air lines directly to the valve. Such valves have also typically been designed for either manual or automatic operation and any attempts to adapt one valve to the other purpose has been less than satisfactory.